Temperature dependent phenomena in liquid LBE alloy

The liquid lead-bismuth eutectic (LBE) alloy is of great interest for applications in future nuclear reactors. The structure and clustering of alloying elements have been investigated on an extended range of temperature (125-720 °C) by high temperature X-ray diffraction (HT-XRD), XPS and scanning photoemission microscopy (SPEM) at the ELETTRA synchrotron in Trieste. After melting the short-range order in liquid metal corresponds to a cuboctahedral arrangement of atoms that progressively evolves towards an icosahedral one as temperature increases. Such process, which is completed around 720 °C, is accompanied by a micro-chemical re-arrangement of atoms with changes of cluster size and composition. At high temperature the atom distribution results to be more homogeneous and the average size of clusters noticeably smaller.